US3654771A - Cam and ice machine combination - Google Patents

Abstract

This specification discloses a machine for making ice cubes in an inverted tray having a closure platen and having an improved cam for forcing the platen open at the beginning of the harvest cycle. In its preferred form a double eccentric cam is used. Generally there is clearance or slack that must be taken up at the beginning of cam rotation before maximum force is required. The cam is so oriented relative to the follower that maximum force is developed by the cam at a point of rotation after the slack has been taken up between the parts and also at a time when the platen is to be broken loose from the ice. The force is applied to the platen continuously through the entire time the platen is being broken away from the ice.

Description

Unite States Patent Kuebler [151 3,654,771 [451 Apr. 11, 1972 C AND ICE MAHINE COMBINATION [72] Inventor: Thomas L. Kuebler, 225 Illinois Avenue,

Erie, Pa. 16505 [22] Filed: Jan. 19, 1970 [21] Appl. No.: 3,620

Primary Examiner-William E. Wayner Attorney-Charles L. Lovercheck [57] ABSTRACT This specification discloses a machine for making ice cubes in an inverted tray having a closure platen and having an improved cam for forcing the platen open at the beginning of the harvest cycle. In its preferred form a double eccentric cam is used. Generally there is clearance or slack that must be taken up at the beginning of cam rotation before maximum force is required. The cam is so oriented relative to the follower that maximum force is developed by the cam at a point of rotation after the slack has been taken up between the parts and also at a time when the platen is to be broken loose from the ice. The force is applied to the platen continuously through the entire time the platen is being broken away from the ice.

5 Claims, 7 Drawing Figures PATENTEDAPR 11 I972 33, 654. 771

sum 1 UF 3 2/ 21 IN VEN TOR THOMAS L. KUIBLER QM W PATENTEDAPRHIHIB 3,654,771

' SHEET 3BF 3 FIG. 6. F G? 3 THOMAS KUEBLEK CAM AND ICE MACHINE COMBINATION STATEMENT OF INVENTION This invention relates to ice cube making machines and, more particularly, to ice cube machines in combination with an improved cam wherein an inverted refrigerated ice cube tray receives jets of water for forming cubes and a swinging platen closes the bottom of the tray to form square ended cubes.

REFERENCE TO PRIOR ART An ice cube machine of the type disclosed herein is shown in Bayston-Kuebler US. Pat. No. 3,009,336.

OBJECTS OF THE INVENTION It is an object of the invention to provide an improved combination ice cube machine and cam for opening the platen during the harvest cycle.

Another object is to provide an improved ice cube machine.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross sectional view of an ice cube machine according to the invention.

FIG. 2 is a longitudinal cross sectional view of the machine taken at another plane through the center of the tray.

FIG. 3 is a view of a double eccentric cam.

FIG. 4 is another view of the double eccentric cam.

FIG. 5 is another view of the double eccentric cam.

FIG. 6 is a front view of a double eccentric cam.

FIG. 7 is a side view of the cam shown in FIG. 6.

DETAILED DESCRIPTION OF THE DRAWINGS The machine disclosed may be made up ofsectional freezing units 11 which may be stacked on base section 10. Eachsection 11 will be made up of an enclosedcabinet 22 which may be suitably insulated to prevent the loss of heat in a manner well known to those skilled in the art. The top of the machine will be provided with asuitable access cover 12 through which access may be had to the mechanism of the machine.

The base is the ice storage bin withbottom 15, back wall 7 14 andend walls 13, and has adoor 16 hinged at 17 at the bottom.Adjustable feet 21 at the corners of the base permit leveling the machine.

Each of thefreezing units 11 has apartition 26 which separates the evaporator housing 27 from thecompression housing 28.

Located incompartment 28 is the refrigeration system comprising thecompressor 51,condensing coil 53, fan 54,heat exchanger 56,refrigerant tank 61, hotgas bypass valve 71, andpressure valve 79.

The freezing apparatus enclosed incabinet 22 will be familiar to those skilled in the art and similar to that disclosed in US. Pat. No. 3,009,336.

The freezing mechanism is characterized by a freezing evaporator generally indicated at 31 consisting of metallic grid havingmarginal walls 32 and shorter intersectingpartition walls 33 all secured on the underside of atop plate 34 to form a multiplicity of individually open bottomedfreezing cells 35. The open bottoms of the individual freezing cells are arranged to be closed during the freezing cycle of the machine byflat water plate 36 mounted in arectangular frame 37 which is in turn pivoted on thepins 38 by ahinge 39. The hinged arrangement is such that the water plate may be raised into contact with the freezing cell grid in a position indicated at A, when the freezing cycle is in process.

Water for the cubes to be frozen is externally provided throughconnection 75 and controlled bysolenoid valve 76. The water is passed throughline 77 totop plate 34, through holes 78 intochambers 35, precooling and passing out through holes inwater plate 36 to thetank 92. Arecirculating pump 96 passes the water from thetank 92 throughbaffle tube 97,filter 98,header 95,tubes 94 withperforations 93 to freezingcells 35. Some of the water is frozen to the periphery of thecells 35 and some recirculates to thetank 92, until the cubes are complete in thecells 35. Thewater plate 36 may thereafter be lowered to position B to permit release and discharge of the ice cubes from the freezing cells as will hereinafter be described.

The rocking movement of the freezer plate is accomplished by a motor connected through appropriate reduction gearing to theoperator shaft 42 having pairedarms 43, each con nected by atension spring 44 to alateral stud 45 projecting from thewater plate 36. Thus, when the motor is rotated to swing thearms 43 upward to the position A, thetension springs 44 will be slightly extended to hold the water plate snugly but resiliently against the bottom edges of the freezing cell walls.

Downward swinging movement of thewater plate 36 and its frame away from the freezingcells 35 is accomplished by energizing the motor to move theshaft 42 approximately a half turn. This causes the parts to swing from position A to position B and allow thewater plate 36 to assume an angle of about 30 degrees to the horizontal. It will be noted that thearms 43 are each provided with acam surface 47 arranged to engage the top edges of the water plate frame and urge theframe 37 downwardly with sufficient force to loosen it from theice cube grid 31 after the freezing operation has taken place.

Releasing the ice cubes formed in thecells 35 is accomplished by heating thecells 35 with hot gases introduced into theevaporator coil 65 byvalve 71 in the manner disclosed in US. Pat. No. 3,009,336. The cubes fall from thecells 35 and are directed by thewater plate 36 to the chute 141 through which they fall into the bin 10.

A drainage system removes excess water from the bin 10 throughtubes 132 and 133 intotrap 134 and out byconnection 135. Atube 83 from thedrain pan 82 of thefreezing section 11 collects the overflow water fromtank 92 and thefreezing cells 35 andplate 36 which deflector plates I42 prevent from flowing into the ice chute 141.

The control system may be, for example, the same as shown in U.S. Pat. No. 3,009,336. The armature 46, the pilot water tank and water level switch 107,nozzle 118,switch 125, switch 131,actuator 139, activator of the control are shown.

It is thecam 47 in combination with the machine that constitutes the subject matter of the present invention.

The US. Pat. No. 3,009,336 discloses a simple cam. The machines with which applicant is familiar, which have been made according to this patent, have used a circular cam on a shaft to force the water plate away from the ice cubes formed in the ice cube tray shown in said patent. In the machine made according to the said patent, there is considerable slack between the parts of the machine and some strain movement takes place between various parts before maximum force is required to break the plate loose from the ice tray. This total preliminary movement may be up to one-third of the total travel of the cam.

The rate of linear travel of a cam follower varies with the reciprocal of the moment arm. The moment arm is the perpendicular from the shaft center to the line through the eccentric center parallel to the direction of travel.

For example, a cam that is vertically eccentric and a flat follower travelling vertically with 90 shaft turn delivering a travel of 1.5, the moment arm is zero at start and increases to 1.5 at finish. Rate of travel is, therefore, zero at start and increases to maximum at finish. Deliverable force is theoretically infinite at start and decreases to 0.667 (minimum) at finish. With the vertical cam, the force available has dropped from infinite to less than 1.0 in less than a third of the travel of the follower and the force continues to drop during the next part of travel when needed most.

A better cam is a perfect spiral involute, which has a constant moment arm (the radius of the development circle), and

thus a constant force available through the whole travel. For a total travel in 90 of 1.5, the moment arm is 3/11, thus the force is 1r/3 or 1.05. A perfect spiral involute is difficult to make and a 45 offset eccentric gives a fair approximation of it. For total travel of 1.5, the eccentricity begins at 0.75, increases to and decreases back to 0.75. The force available thus varies from 1.33 to 0.943 at mid point of travel and back to 1.33 at end of travel. Compared to the vertical eccentric, the offset eccentric takes up the slack quicker and has a force greater from about the one-fourth travel point on and a minimum force 41 percent greater than the minimum force of the vertical eccentric.

Even though the offset eccentric is better than the vertical eccentric, it still produces more force during slack take up than it does when the greatest force is needed at about the one-third travel point. Also it produces more force at the end of the travel when the needed force is usually reduced during the overtravel period.

A much superior cam (even superior to a perfect spiral involute) is one whose force peaks at the point of travel where the needed force is greatest and whose force is less during slack take up and during overtravel. The cam which produces this type of force curve is a double eccentric whose moment arm (instead of increasing during slack take up, or remaining constant per spiral) decreases during slack take up, reaches a minimum near the point of greatest needed force and then increases during overtravel. Instead of having a single radius, as do the vertical and offset eccentric cams, the double eccentric cam has curves with two different radii in the operational area, with the smaller radius effective first then the large radius, with the juncture or tangent point in line with the line running through the radiis centers. The smaller radius (Rs) may be any practical or convenient radius, the larger radius (RL) is the smaller radius plus the center line distance.

When the cam is at rotation, (l if the center (Cs) of the smaller radius is on the horizontal axis (X) and the center (CL) of the larger radius is on the vertical axis (Y) with respect to the center of rotation of the cam, the center line distance (D) equals the total linear travel delivered for 90 rotation; see FIG. 3; (2) If Cs is below X axis, D is increased by Cs displacement from X axis; (3) If Cl is off the Y axis away from Cs, D is increased by that displacement, (4) If Cs is above the X axis or Cl is off the Y axis toward Cs, D is reduced by the sum of these displacements. This (4) is not a preferred design as it reduces the effectiveness of the double eccentric and carried to the ultimate (each displacement equal to half the total travel), the cam becomes a single offset eccentric. The peak force occurs when the cam rotates the center line to the vertical as the moment arm is then smallest being the perpendicular from the shaft to the center line. This rotation is equal to the angle between the Y axis and the center line. The ratio of travel to this point compared to total travel is equal to the sine squared of this angle. The desired ratio is thus equated to the sine squared to determine the correct angle. i.e. If peak force is desired at one-fourth travel, then sine squared of the angle equals 0.25 and sine of the angle is 0.25 which equals 0.5 and the angle is 30. If peak force is desired at one-half travel, the angle is 45, etc. In the example shown in FIGS. 3, 4, 5, which is a preferred embodiment of the invention, the angle is the small angle ofa 3, 4, 5, triangle, whose sine is 0.6, sine squared is 0.36 so peak force occurs at 36 percent of total travel; Cs and CL are placed on X axis and Y axis, so that D is 1.5 to give total travel of 1.5.

FIG. 3 shows the cam at 0 rotation, the moment arm MA is 0.9, the relative force is l/O.9 1.1 l, the vertical travel is 0.

FIG. 4 shows the same cam at 3650 rotation counterclockwise, the moment arm MA is 0.72 at its minimum, the relative force is l/0.72 1,39 its maximum. The vertical travel is 0.54 36 ofthe 1.5 designed travel.

FIG. 5 shows the cam at 90 rotation counterclockwise to its design limit, the moment arm MA is 1.2, the relative force is H1 .2 0.83, its design minimum. The travel is 1.5 100 percent of the 1.5 designed travel.

The foregoing specification sets forth the invention in its preferred practical forms but the structure shown is capable of modification within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells,

means for introducing a liquid to be frozen into said cells to be subjected to alternate freezing and defrosting cycles,

a platen movable to evaporator closing position during an ice freezing cycle and to an open ice discharge position during a defrosting cycle, wherein ice is formed in said cells and upon said platen during the freezing cycle and freed from said cells during the defrosting cycle,

a cam shaft mounted on said machine above said platen,

a cam on said shaft engageable with said platen,

and power means operable following the said freezing cycle to actuate said cam shaft and cam to depress said platen for forced separation from said evaporator and ice upon said cam being rotated to one position and permit said platen to close said evaporator when said cam is moved to another position,

said cam having a first part having a first center of curvature and a second part having a second center of curvature,

said cam being mounted on said shaft at a position spaced from said first center of curvature and from said second center of curvature whereby a double eccentric cam is formed,

said cam being adapted to move said platen first through a large excursion with a small force to take up slack in the platen, then through a small excursion with a larger force to move said platen open.

2. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells,

means for introducing a liquid to be frozen into said cells ing cycle, wherein ice is formed in said cells and upon said platen during said freezing cycle and freed from said cells during said defrosting cycle,

a cam shaft mounted on said machine extending over said platen adjacent the free end thereof,

a cam on said shaft engageable with the free end of said platen,

and power means operable to rotate said shaft and cam one revolution following the said freezing cycle for moving cam from a position to permit said platen to close said evaporator to a position to break it away from the ice formed therein and permit free swinging thereof to its open ice discharging position,

said cam having a first part having a first center of curvature and a second part having a second center of curvature,

said cam being mounted on said shaft disposed at a position spaced from said first center of curvature and from said second center of curvature, and adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

3. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells,

a platen movable into and away from sealing engagement with said evaporator,

a liquid supply tank carried by said platen,

a liquid supply head in said platen having a spray nozzle directed upwardly and centrally of each cell and a waste drainage port leading therefrom to said supply tank,

and a pump carried by said platen adjacent said tank having its inlet connected with said tank and its discharge connected with said spray nozzles for circulating the liquid to be frozen through said cells and tank, the platen, supply tank, pump and liquid passage therebetween being a rigid unitary structure and hinged at one end of the platen to permit said structure to swing downwardly and away from the under side of said evaporator,

and power means operable between another edge of the platen and evaporator for forcibly breaking the ice seal,

a cam having a first part having a first center of curvature and a second part having a second center of curvature,

said cam being mounted on a shaft disposed at a position spaced from said first center of curvature and from said second center of curvature,

said cam adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

4. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells,

a platen movable into and away from sealing engagement with said evaporator,

a liquid supply head in said platen having a spray nozzle directed upwardly into each cell and a waste drainage port leading therefrom,

a liquid supply tank secured to and carried by said platen,

a pump mounted on said platen having its inlet connected with said tank and its discharge connected with said spray nozzles for circulating the liquid tobe frozen through said cells and tank,

a source of liquid connected with said tank having a control valve,

and a float in said tank operably connected with said valve for limiting the liquid level therein,

said platen, liquid supply head, supply tank, pump and interconnecting passages being assembled as a rigid unitary structure and relatively movable as a unit with respect to said evaporator,

a cam having a first part having a first center of curvature and a second part having a second center of curvature,

said cam being mounted on a shaft disposed at a position spaced from said first center of curvature and from said second center of curvature,

said cam adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

5. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells,

a platen,

said platen being hinged at one side to swing into and away from sealing engagement with said evaporator,

a liquid supply head in said platen having a spray nozzle directed upwardly into each cell and a waste drainage port leading therefrom,

a liquid supply tank carried by the other side of said platen movable therewith,

a pump carried by said platen having its inlet connected with said tank and its discharge connected with said spray nozzles for circulating the liquid through said cells and tank during an ice forming freezing cycle, wherein ice is formed within said cells and upon said platen head during the freezing cycle and freed therefrom during a defrosting cycle,

a pressure exerting member mounted on said machine engageable with said platen in a direction to depress it for forced separation from said evaporatorand ice and power means operable to actuate said member following the said freezing cycle,

a cam having a first part having a first center of curvature and a second part having a second center of curvature,

said cam being mounted on a shaft disposed at a position spaced from said first center of curvature and from said second center of curvature,

said cam adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

Claims (5)

1. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells, means for introducing a liquid to be frozen into said cells to be subjected to alternate freezing and defrosting cycles, a platen movable to evaporator closing position during an ice freezing cycle and to an open ice discharge position during a defrosting cycle, wherein ice is formed in said cells and upon said platen during the freezing cycle and freed from said cells during the defrosting cycle, a cam shaft mounted on said machine above said platen, a cam on said shaft engageable with said platen, and power means operable following the said freezing cycle to actuate said cam shaft and cam to depress said platen for forced separation from said evaporator and ice upon said cam being rotated to one position and permit said platen to close said evaporator when said cam is moved to another position, said cam having a first part having a first center of curvature and a second part having a second center of curvature, said cam being mounted on said shaft at a position spaced from said first center of curvature and from said second center of curvature whereby a double eccentric cam is formed, said cam being adapted to move said platen first through a large excursion with a small force to take up slack in the platen, then through a small excursion with a larger force to move said platen open.

2. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells, means for introducing a liquid to be frozen into said cells adapted to be subjected to alternate freezing and defrosting cycles, a platen having one end pivotally mounted adjacent said evaporator unit and the other end free to swing to evaporator closing position during an ice freezing cycle and to an open ice discharging position during a defrosting cycle, wherein ice is formed in said cells and upon said platen during said frEezing cycle and freed from said cells during said defrosting cycle, a cam shaft mounted on said machine extending over said platen adjacent the free end thereof, a cam on said shaft engageable with the free end of said platen, and power means operable to rotate said shaft and cam one revolution following the said freezing cycle for moving cam from a position to permit said platen to close said evaporator to a position to break it away from the ice formed therein and permit free swinging thereof to its open ice discharging position, said cam having a first part having a first center of curvature and a second part having a second center of curvature, said cam being mounted on said shaft disposed at a position spaced from said first center of curvature and from said second center of curvature, and adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

3. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells, a platen movable into and away from sealing engagement with said evaporator, a liquid supply tank carried by said platen, a liquid supply head in said platen having a spray nozzle directed upwardly and centrally of each cell and a waste drainage port leading therefrom to said supply tank, and a pump carried by said platen adjacent said tank having its inlet connected with said tank and its discharge connected with said spray nozzles for circulating the liquid to be frozen through said cells and tank, the platen, supply tank, pump and liquid passage therebetween being a rigid unitary structure and hinged at one end of the platen to permit said structure to swing downwardly and away from the under side of said evaporator, and power means operable between another edge of the platen and evaporator for forcibly breaking the ice seal, a cam having a first part having a first center of curvature and a second part having a second center of curvature, said cam being mounted on a shaft disposed at a position spaced from said first center of curvature and from said second center of curvature, said cam adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

4. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells, a platen movable into and away from sealing engagement with said evaporator, a liquid supply head in said platen having a spray nozzle directed upwardly into each cell and a waste drainage port leading therefrom, a liquid supply tank secured to and carried by said platen, a pump mounted on said platen having its inlet connected with said tank and its discharge connected with said spray nozzles for circulating the liquid to be frozen through said cells and tank, a source of liquid connected with said tank having a control valve, and a float in said tank operably connected with said valve for limiting the liquid level therein, said platen, liquid supply head, supply tank, pump and interconnecting passages being assembled as a rigid unitary structure and relatively movable as a unit with respect to said evaporator, a cam having a first part having a first center of curvature and a second part having a second center of curvature, said cam being mounted on a shaft disposed at a position spaced from said first center of curvature and from said second center of curvature, said cam adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a Force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

5. In a machine for manufacturing ice comprising an evaporator unit including a plurality of open bottom ice forming cells, a platen, said platen being hinged at one side to swing into and away from sealing engagement with said evaporator, a liquid supply head in said platen having a spray nozzle directed upwardly into each cell and a waste drainage port leading therefrom, a liquid supply tank carried by the other side of said platen movable therewith, a pump carried by said platen having its inlet connected with said tank and its discharge connected with said spray nozzles for circulating the liquid through said cells and tank during an ice forming freezing cycle, wherein ice is formed within said cells and upon said platen head during the freezing cycle and freed therefrom during a defrosting cycle, a pressure exerting member mounted on said machine engageable with said platen in a direction to depress it for forced separation from said evaporator and ice, and power means operable to actuate said member following the said freezing cycle, a cam having a first part having a first center of curvature and a second part having a second center of curvature, said cam being mounted on a shaft disposed at a position spaced from said first center of curvature and from said second center of curvature, said cam adapted to exert a force of small magnitude to take up slack, a force of large magnitude to break said platen loose from said ice, then a force of small magnitude to force said platen open, during three substantially equal angular excursions of said cam respectively.

Images